Re: [PATCH tip/core/rcu 07/13] vfs: apply lockdep-based checkingto rcu_dereference() uses

[Peter Zijlstra]

On Thu, 2010-02-11 at 16:00 -0800, Paul E. McKenney wrote:
> 
> -#define files_fdtable(files) (rcu_dereference((files)->fdt))
> +#define files_fdtable(files) \
> +       (rcu_dereference_check((files)->fdt, \
> +                              rcu_read_lock_held() || \
> +                              lockdep_is_held(&(files)->file_lock) ||
> \
> +                              atomic_read(&files->count) == 1))
>  
>  struct file_operations;
>  struct vfsmount;
> @@ -78,7 +82,7 @@ static inline struct file * fcheck_files(struct files_struct *files, unsigned in
>         struct fdtable *fdt = files_fdtable(files);
>  
>         if (fd < fdt->max_fds)
> -               file = rcu_dereference(fdt->fd[fd]);
> +               file = rcu_dereference_check(fdt->fd[fd], rcu_read_lock_held() || lockdep_is_held(&files->file_lock) || atomic_read(&files->count) == 1);
>         return file; 

I'm almost thinking you can do something smart here and not replicate
that condition :-)


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/